In placental mammals, the umbilical cord (UC) connects the developing fetus to the placenta. The UC consists of veins and arteries embedded in Wharton's jelly which, in turn, is encased in a layer of amniotic epithelial lining (FIG. 1). The Wharton's jelly and the layer of amniotic epithelial lining comprise the umbilical tissue (UT), while the veins and arteries are the umbilical blood vessels.
The native components of UT include endogenous cells, extracellular matrix (ECM), and bioactive factors. Endogenous cells found in UT include amniotic epithelial cells and stromal cells in Wharton's jelly, such as neonatal fibroblasts, myofibroblasts, mesenchymal stem cells, and macrophages. The ECM of UT is largely made up of collagen, mucopolysaccharides (hyaluronic acid (HA) and chondroitin sulfate). Bioactive factors consist of, but are not limited to, growth factors, cytokines, and anti-microbial peptides. The native components of UT, including endogenous cells, ECM, and bioactive factors, are known to be beneficial for tissue repair and reconstruction. Therefore, there is a need to develop an UT product that removes all immunogenic components (the umbilical blood vessels) of the UC and preserves all of the components of UT.
UT cells (amniotic epithelial cells and Wharton's jelly cells) are known to have therapeutic potentials—they can secrete additional bioactive factors and ECM proteins; they can engraft in local tissues; and they can differentiate into other cells types. A process that keeps UT cells alive and is able to cryopreserve a large area of a relatively thick tissue (>1 mm in thickness) without sacrificing the cell viability is needed.